The article states that the Phobos mission would still collect a boulder. It just has to be smaller than one collected from an asteroid.

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Still, is 5 tons of a Martian moon worth more than 70 tons of an asteroid? If you want to send people to Mars, arguably it is.

I agree.

NAC says they should go to Mars whether they can get a sample or not.

Even if they don't do the ARM grab a boulder routine, there should be some sort of sample return. If not, why bother to fly to Phobos?

We already know SEP works from previous long duration missions. If all they want to do is test the engines on a large SEP tug then just fly it to the Moon and back.

If they are going to have a SEP tug go to Phobos, it should bring something back. Otherwise, it is just as uninspiring and pointless as sending a manned Orion to DRO so the crew can twiddle their thumbs.

The article states that the Phobos mission would still collect a boulder. It just has to be smaller than one collected from an asteroid.

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Still, is 5 tons of a Martian moon worth more than 70 tons of an asteroid? If you want to send people to Mars, arguably it is.

I agree.

NAC says they should go to Mars whether they can get a sample or not.

Even if they don't do the ARM grab a boulder routine, there should be some sort of sample return. If not, why bother to fly to Phobos?

We already know SEP works from previous long duration missions. If all they want to do is test the engines on a large SEP tug then just fly it to the Moon and back.

If they are going to have a SEP tug go to Phobos, it should bring something back. Otherwise, it is just as uninspiring and pointless as sending a manned Orion to DRO so the crew can twiddle their thumbs.

It seems logical for there to be some sort sample return, given that NAC is saying test SEP to Mars and then to lunar orbit. Making the full round trip really asks for sample return, even if it's just sort of tacked on to what NAC says should be the main technology demonstration mission.

Still, I don't see it as uninspiring and pointless even if there is no sample return. I didn't think technology demonstration missions like Deep Space 1 or EO-1 were uninspiring and pointless. I don't think the robotic planetary science missions to Mars have been uninspiring and pointless. If some remote sensing instruments, cubesats, secondary technology demonstrations, or things like that were added, it could be a nice mission.

I also don't think it's worth fighting over whether the mission goes to an asteroid, Phobos, Deimos, or whatever. If switching the mission to Mars moons or generally Mars orbit gets the NAC behind it, and maybe lets some in Congress support it by letting them score a few points, that's fine. Doing the Mars mission would make it much easier to do a mission like ARM later, anyway, so ARM advocates should support this variation, too (since they are currently likely to get nothing). Mars advocates would benefit. Planetary science might benefit more from a Mars mission than an asteroid mission since the mission could study both Mars moons and Mars itself. Advocates of Obama's original push for technology demonstration and robotic precursor missions would benefit since that's what this mission would be, and SLS/Orion advocates would benefit if SLS launches the robotic missions and there is a sample return component for SLS/Orion to study or retrieve. Commercial/ISRU interests could still benefit if Mars moon samples are returned or the moons are studied.

Phobos or Deimos are probably more relevant. I assume returning anything substantial from there would be a lot more expensive in delta-v, time and money though.

I was very interested in the manned portion and extending it to a permanent high lunar orbit station investigating asteroid ISRU and humans interacting with a Phobos/Deimos-like environment, and also testing all the BEO tech that ISS is not suitable for due to all the sensitive microgravity work.

It is also possible that Phobos/Deimos will turn out very dry whereas we may be able to select NEOs with high (eg 20%) volatile content. This could make these objects more relevant to mars than the moons of mars. It shouldnt be one or the other, we should examine all these (compared to mars HSF) easy targets.

That would be a bad idea. It'd mean you couldn't demonstrate the Enhanced Gravity Tractor and the boulder you'd get would be much, much smaller.

The enhanced gravity tractor demo should /not/ be underestimated. By using this method, humanity will demonstrate the precise maneuvering of an asteroid larger than Apophis. That alone would be worth the $1.25 billion price tag. And a larger boulder would allow real scale demonstration of ISRU, allowing us to fill up 90% of our propellant in orbit without having to launch it from Earth. That would also be a game changer and well worth the mission cost (although this part would likely be demonstrated by commercial companies).

Phobos (or Deimos) would be a good second mission, though. But following NAC's poor advice would dramatically reduce the value of ARM.

Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Science journalist Miles O’Brien, who characterized an asteroid as a “contrived destination, seized upon this idea. “People would get excited about that. I could sell that to editors.”"

No doubt anything NASA does can get attention to some degree, but Mars is certainly a place that is recognizable for the largest segment of the public that cares to notice anything about space. Just from an ROI standpoint on the U.S. Taxpayers funding of NASA, an SEP mission to Mars may make better sense than the ARM, especially if we can gather samples at Phobos.

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If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Ron: You'll have to tell the thousand individuals in Russia injured by the asteroid impact there that asteroids are merely contrived.

It's NASA's job to address the asteroid threat. Phobos does not address that, the asteroid picked for Option B certainly does. Because of that, bang for the buck is much higher for actually redirecting the asteroid.

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Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

SLS will need to launch something that will actually garner some genuine public interest. Public interest translates into Congressional support. Without that support SLS will soon enough cease to exist except as a data point in NASA's growing list of cancelled programs. A mission to Phobos at Mars will get that interest. With no disrespect to the Russian people intended, they don't have representatives in our Congress so their opinion of asteroids doesn't count in this case. We have to be pragmatic here.

To all you SLS supporters out there - get NASA to do something with SLS that will gain real public interest, like Mars, if you want to keep your rocket. ARM will not get that kind of interest. The flight rate of SLS is dismal as it is. Don't waste one on something that the public won't care about except for how much it cost them. That's a sure fire way to dribble away what little support there actually is.

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Chuck - DIRECT co-founderI started my career on the Saturn-V F-1A engine

The enhanced gravity tractor demo should /not/ be underestimated. By using this method, humanity will demonstrate the precise maneuvering of an asteroid larger than Apophis. That alone would be worth the $1.25 billion price tag. And a larger boulder would allow real scale demonstration of ISRU, allowing us to fill up 90% of our propellant in orbit without having to launch it from Earth. That would also be a game changer and well worth the mission cost (although this part would likely be demonstrated by commercial companies).

Phobos (or Deimos) would be a good second mission, though. But following NAC's poor advice would dramatically reduce the value of ARM.

I like everything you've written here. ARM supporters have been shouting this into the wind. It's the most practical mission I can imagine for a rocket that's eminently unpractical.

It seems to me that NASA should never have attempted to cast ARM as a stepping stone to Mars, except perhaps as a secondary consideration. ARM should be sold as NEO mitigation first, asteroid mining second, and stepping stone third. If the general public saw ARM as asteroid mitigation, they'd be cheering for it, and Congress can't very well call Bolden on the carpet for trying to save humanity.

Perhaps the manned aspect was sufficiently weak that they didn't feel it could be sold that way to Congress. But Congress doesn't want to cancel SLS; it's their rocket, after all. They just want something for SLS to do that the public will find inspiring.

The enhanced gravity tractor demo should /not/ be underestimated. By using this method, humanity will demonstrate the precise maneuvering of an asteroid larger than Apophis. That alone would be worth the $1.25 billion price tag. And a larger boulder would allow real scale demonstration of ISRU, allowing us to fill up 90% of our propellant in orbit without having to launch it from Earth. That would also be a game changer and well worth the mission cost (although this part would likely be demonstrated by commercial companies).

Phobos (or Deimos) would be a good second mission, though. But following NAC's poor advice would dramatically reduce the value of ARM.

I like everything you've written here. ARM supporters have been shouting this into the wind. It's the most practical mission I can imagine for a rocket that's eminently unpractical.

It seems to me that NASA should never have attempted to cast ARM as a stepping stone to Mars, except perhaps as a secondary consideration. ARM should be sold as NEO mitigation first, asteroid mining second, and stepping stone third. If the general public saw ARM as asteroid mitigation, they'd be cheering for it, and Congress can't very well call Bolden on the carpet for trying to save humanity.

Perhaps the manned aspect was sufficiently weak that they didn't feel it could be sold that way to Congress. But Congress doesn't want to cancel SLS; it's their rocket, after all. They just want something for SLS to do that the public will find inspiring.

NASA is not doing a good job of selling their missions to Congress. ARM should be cast as a planetary defense test and asteroid mining research.

Other missions should be direct stepping stones to manned exploration of Mars by, dare I write it, going to Mars.

With enough build up and data to back it up, Bolden could get Congress to approve two SEP tests, ARM and a Phobos mission. After all, they can be payloads for Congress' SLS. It could be the same SEP tug for both missions. That should keep the costs down and prove it works.

NASA scientists and engineers come up with great ideas. I think the problem is NASA management doesn't know which ideas to back and doesn't know how to sell their ideas to Congress.

Forget for a moment that we're talking the kabuki theater called Government. Bolden is trying to convince a group of people to fund missions. From a sales point of view, it's like a salesman trying to get a company to buy his product.

Look at the expensive AMS experiment. Dr. Ting did a great job of convincing Congress to fund AMS. It is on ISS right now gathering data. You got to know how to sell your project.

Didn't congress actually mandate that the NASA Administration think up a Cis-lunar mission utilizing the SLS?

Given the fact their is no lunar lander the ARM concept is the ONLY possible thing that NASA could have offered that fits this criteria. But it seems that congresses ability to irrationally hate anything coming out of the white house has made them forget their own mandate. Congress still has no one but itself to blame because they NEVER allocate money for anything to go on top of SLS.

I find the Phobos re-direct idea rather silly, it comes off as an attempt to just 'Mars up' an idea to try to portray it as being more 'on the road to Mars' for people who don't understand anything about the actual technical challenges. SEP vehicles have already been well past Mars, the DISTANCE is trivial and not an improvement over current capabilities. Moving more MASS is what we need to demonstrate with SEP, that's why I favored the 'bag-and-wrap' Option A for ARM because it was a higher mass goal.

I find the Phobos re-direct idea rather silly, it comes off as an attempt to just 'Mars up' an idea to try to portray it as being more 'on the road to Mars' for people who don't understand anything about the actual technical challenges. SEP vehicles have already been well past Mars, the DISTANCE is trivial and not an improvement over current capabilities.

What makes you think they see it as capability demonstration at all? Actually knowing if there is resources on Phobos or Deimos that could be exploited for a landing mission would be on the road to Mars.

ARM option B would test out a gravity tractor. As neat as that is what is the chance of devastating impact happening in the next few decades? I am not sure of the wisdom in developing a technology which might not be needed for millennia. Let me posit this though, if the threat of an asteroid impact causes real concern why not use the money to fund something like the B612 Foundation's Sentinel telescope so we could find all the potentially dangerous asteroids? If there is a rock heading at us the most pressing thing is to find it as soon as possible. Funding will materialize for all sorts of deflection strategies in short order.

The problem with that, though, is we would be relying on untested deflection techniques in that case. Also, part of ARM is to survey more asteroids.

Asteroid impact is low probability but very high severity. A large impact in the Pacific could easily kill millions via tsunami. It's dumb to discount such a severe impact just because it /probably/ won't happen soon.

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Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Hehe.. I find that terminology slightly worrying. Imagine towing Phobos into high lunar orbit. "Look what I found, mum!"

However my understanding is that the original NAC proposal did not mention sample return at all, which begs an obvious question...

Stop. The Keck Study upon which this is based mentioned sample return. (EDIT: "sample" occurs 22 times in the Keck study)

« Last Edit: 05/05/2015 12:35 AM by Robotbeat »

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Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

ARM option B would test out a gravity tractor. As neat as that is what is the chance of devastating impact happening in the next few decades? I am not sure of the wisdom in developing a technology which might not be needed for millennia. Let me posit this though, if the threat of an asteroid impact causes real concern why not use the money to fund something like the B612 Foundation's Sentinel telescope so we could find all the potentially dangerous asteroids? If there is a rock heading at us the most pressing thing is to find it as soon as possible. Funding will materialize for all sorts of deflection strategies in short order.

The two don't necessarily have to be mutually exclusive. I'd like to see both something like the Sentinel mission funded as well as ARM. You want detection, but you also want to demonstrate the Enhanced Gravity Tractor technique. It has its fair share of subtleties that you'd want to iron out when the time isn't critical.

Using ARM to test a gravity tractor is begging the question of the danger of asteroid impacts, it assumes that in the near future there will be one. According to Dr. Binzel the creator of the Torino Scale an asteroid impact which causes local destruction to an inhabited place happens on average of once every 10,000 years. Larger events happen much more rarely. If there is no threat there is no need to develop countermeasures.

ARM will cost at a minimum $1.25 billion and likely much more than that. For a small fraction of that a very intensive search for dangerous NEOs can be done. If that turns up anything bad then the government will effectively write a blank check to deal with it. NASA leadership has been talking about ARM for a while but only recently asked for money to conduct a search. Now they are saying that they don't even need to search because they have already picked the asteroids they want to target from the known catalog. ARM as it is being proposed now will not do the most simple, inexpensive, and important step of asteroid risk mitigation.

Using ARM to test a gravity tractor is begging the question of the danger of asteroid impacts, it assumes that in the near future there will be one. ...

No it doesn't. It only presumes there's a risk of an asteroid impact sometime within, say, the next century. By developing the tech sooner, this gives us a much better chance of deflecting an asteroid once it is determined to be a hazard.

You don't ignore the risk just because it's not guaranteed to kill you.

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Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Using ARM to test a gravity tractor is begging the question of the danger of asteroid impacts, it assumes that in the near future there will be one. ...

No it doesn't. It only presumes there's a risk of an asteroid impact sometime within, say, the next century. By developing the tech sooner, this gives us a much better chance of deflecting an asteroid once it is determined to be a hazard.

You don't ignore the risk just because it's not guaranteed to kill you.

There will always be a risk until the entire population is known. At some point that risk becomes low enough that the available finite funding is best spent on more pressing things. The the analysis based on what we know now is that over the next 100 years there is a 99% chance that a gravity tractor demo will be useless. Over time a demo will become less and less relevant. New technologies will appear, information on the demo may be lost, or some other event happens which causes enough damage to render the threat moot.

Every new NEO which is discovered retires some of the statistical risk. We can discover and catalog a good enough number of them to retire the risk to negligible levels very quickly and cheaply. Option A which was the original plan made a search like this mandatory. Option B makes such a search totally unnecessary. If ARM really is about planetary protection then option A is the best one to go with. Even if it gets canceled before it flies it will have accomplished a lot just by conducting a search for targets. Having the ability to divert a threat is useless if the threat is unknown.

Using ARM to test a gravity tractor is begging the question of the danger of asteroid impacts, it assumes that in the near future there will be one. ...

No it doesn't. It only presumes there's a risk of an asteroid impact sometime within, say, the next century. By developing the tech sooner, this gives us a much better chance of deflecting an asteroid once it is determined to be a hazard.

You don't ignore the risk just because it's not guaranteed to kill you.

There will always be a risk until the entire population is known. At some point that risk becomes low enough that the available finite funding is best spent on more pressing things. The the analysis based on what we know now is that over the next 100 years there is a 99% chance that a gravity tractor demo will be useless. ...

That is a false understanding of the threat. In essence, you're saying we should practice Russian Roulette.

Often you can't know for sure whether an asteroid will impact or not before the window for easy redirect options is well passed (i.e. after it has gone through a gravitational keyhole). If there's a 1 in 100 chance an asteroid may impact and create an enormous tsunami that will kill tens of millions, the smart thing to do isn't to say "oh, geeze, well it probably won't hit." The smart thing to do would be to launch an inexpensive mission to deflect it early enough that deflection can be assured with a cheap vehicle.

There's a near-certainty that we'll be forced to play Russian Roulette in the next century. You're arguing that's just fine.

« Last Edit: 05/05/2015 06:32 PM by Robotbeat »

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Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0